I think that most dishwasher manufacturers recommend that salt is put into the machine to assist with the softening of the water. There is a special receptacle in the dishwasher for this.
That suggests that there is no salt in the dishwasher powders, liquids or tablets (even the triple action ones)
The salt you put in a dishwasher salt chamber does not come into contact with the water used to clean the dishes ... it purely regenerates the chamber at the end of the cycle ... and yes there is salt in 3/4/5 in 1 tablets ... to assist the surfactant in its cleaning process ...